The fabrication of semiconductor devices, or similar types of devices, typically includes a number of processing steps to form desired features and multiple layers on a substrate. In general, the processing steps used to form semiconductor devices on a substrate are well known and includes processes such as deposition, etching, photolithography, and chemical mechanical polishing.
Due to the complexity and need for accuracy in semiconductor fabrication, monitoring and evaluation of the processing is often required. One type of necessary monitoring is defect inspection. Defects are sometimes introduced during processing and typically include contaminants, or other non-uniformities, and scratches. The presences of defects may result in malfunctioning devices and a reduction in the overall yield. Accordingly, defect inspection is used to identify chips with defects as well as to identify processing steps that are causing defects to prevent further defect generation in subsequent processing.